1. Field of the Invention
The present invention generally relates to devices and methods for measuring slope to a target and more specifically to devices and methods for measuring the slope from a golf ball's location on the golf course to the pin or other desired target and selecting a golf club based upon the measured slope.
2. Description of the Related Art
As discussed generally in U.S. Pat. No. 7,239,377 to Vermillion, it is often desirable to determine the distance to a target in various situations. For example, golfers like to know what the distance of their ball is from the green, or a pin positioned on the green, to help them decide what club to select and to decide how hard or forcefully to swing the club. Most golf course fairways are provided with distance markers which provide the golfer with a general idea what the distance to the pin is. However, these conventional markers only provide straight-line distances to the pin and fail to account for the uphill or downhill slope of the golf course to the pin or as discussed in Vermillion the parabolic trajectory of projectiles. As a result, while conventional markers work well on a relatively flat course their usefulness is quite suspect on golf courses with substantial uphill and downhill grades.
The Vermillion patent provides an electronic device which addresses this problem. This electronic device includes a laser range sensor for determining a first range to the target; a tilt sensor for determining an angle to the target relative to the device based on the orientation of the device; a computing element, coupled with the distance sensor and the tilt sensor, for determining a second range by multiplying the first range by a factor corresponding to the determined angle and adding the result to the first range, the second range being a representation of a flat-ground distance the projectile must travel such that the projectile's trajectory intersects the target; and a display, coupled with the computing element, for indicating the first range and the second range.
While Vermillion's electronic device addresses the problem it utilizes electronic components which are somewhat expensive and easily destroyed if the device is accidentally dropped or exposed to the elements as can easily happen on the golf course if it begins raining Lightning which also often occurs on a golf course may also damage or destroy the device's electronics. Vermillion's laser range sensor for determining a first range to the target (i.e. the “straight line distance” to the pin) is also largely unnecessary since most golf courses include distance markers on the fairway which provide the golfer with the actual straight line distance to the pin.